. >> president obama has agreed to delaying miranda rights under public safety measure but rebuffing republicans calling nor for a change in the prosecutorial playbook. he became a u.s. september last year on september 11th. he has the constitutional right to be tried in a civilian court. >> literally hundreds of terrorists, those accused of terrorism have been successfully prosecuted and imprisoned in the united states using the same process that's being used in boston. >> reporter: at the same time lawmakers want to know a lot more about the suspect's dead brother tamerlan tsarnaev traveled to russia for six months after he was brought to the attention of the fbi as a possible islamic extremist. >> we want to know why after he was interviewed and after foreign intelligence service raises a flag on the individual, why he was allowed to travel abroad and yet there were no flags put on him overseas. >> law enforcement and intelligence agencies try to retrace the older brother's steps leading up to the bombing, all eyes are on boston where investigators hope they can get dzhokhar tsarn